Fast cell search

ABSTRACT

Systems and methodologies are described that facilitate searches for a cell in a wireless communication environment. A mobile device can employ a searcher that can detect timing information respectively associated with PSCs and cells to determine the cell with the highest correlation. The searcher can detect SSCs, which can include detecting associated phase information, to determine the SSC with the highest correlation, CP length, and/or other information to facilitate identifying a desired cell having the strongest signal to establish communication between the mobile device and the desired cell. PSCs respectively associated with cells can have different positions in the symbol sequences, and SSCs can respectively be phase shifted at different angles to facilitate detection and identification of a cell(s), where a PSC can be utilized as a phase reference by the associated SSC.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patentapplication Ser. No. 60/884,402 entitled “A METHOD AND APPARATUS FORFAST CELL SEARCH” filed on Jan. 10, 2007. The entirety of theaforementioned application (including appendices) is herein incorporatedby reference.

BACKGROUND

I. Field

The following description relates generally to wireless communications,and more particularly to searching for cells in a wireless communicationsystem.

II. Background

Wireless communication systems are widely deployed to provide varioustypes of communication; for instance, voice and/or data can be providedvia such wireless communication systems. A typical wirelesscommunication system, or network, can provide multiple users access toone or more shared resources (e.g., bandwidth, transmit power, . . . ).For instance, a system can use a variety of multiple access techniquessuch as Frequency Division Multiplexing (FDM), Time DivisionMultiplexing (TDM), Code Division Multiplexing (CDM), 3GPP LTE systems,Orthogonal Frequency Division Multiplexing (OFDM), and others.

Generally, wireless multiple-access communication systems cansimultaneously support communication for multiple mobile devices. Eachmobile device can communicate with one or more base stations viatransmissions on forward and reverse links. The forward link (ordownlink) refers to the communication link from base stations to mobiledevices, and the reverse link (or uplink) refers to the communicationlink from mobile devices to base stations. This communication link canbe established via a single-in-single-out, multiple-in-signal-out, or amultiple-in-multiple-out (MIMO) system.

For instance, a MIMO system can employ multiple (N_(T)) transmitantennas and multiple (N_(R)) receive antennas for data transmission. AMIMO channel formed by the N_(T) transmit and N_(R) receive antennas canbe decomposed into N_(S) independent channels, which are also referredto as spatial channels, where N_(S)≦min {N_(T), N_(R)}. Each of theN_(S) independent channels can correspond to a dimension. The MIMOsystem can provide improved performance (e.g., higher throughput and/orgreater reliability) if the additional dimensionalities created by themultiple transmit and receive antennas are utilized.

A MIMO system can support a time division duplex (TDD) and frequencydivision duplex (FDD) systems. In a TDD system, the forward and reverselink transmissions can be on the same frequency region so that thereciprocity principle allows the estimation of the forward link channelfrom the reverse link channel. This can enable the access point toextract transmit beamforming gain on the forward link when multipleantennas are available at the access point

Wireless communication systems oftentimes employ one or more basestations that provide a coverage area. A typical base station cantransmit multiple data streams for broadcast, multicast and/or unicastservices, wherein a data stream may be a stream of data that can be ofindependent reception interest to a mobile device. A mobile devicewithin the coverage area of such base station can be employed to receiveone, more than one, or all the data streams carried by the compositestream. Likewise, a mobile device can transmit data to the base stationor another mobile device.

A base station can also be referred to as a cell. When searching for acell among a plurality of cells in a communication system (e.g., OFDMsystem), a mobile device can desire to detect information, such asPrimary Synchronization Channels (PSCs) and Secondary SynchronizationChannels (SSCs), generated by respective cells to facilitate locatingand synchronizing with a cell to facilitate communication between thecell and the mobile device. It is desirable to be able to quickly searchand locate a desired cell within a communication system.

SUMMARY

The following presents a simplified summary of one or more embodimentsin order to provide a basic understanding of such embodiments. Thissummary is not an extensive overview of all contemplated embodiments,and is intended to neither identify key or critical elements of allembodiments nor delineate the scope of any or all embodiments. Its solepurpose is to present some concepts of one or more embodiments in asimplified form as a prelude to the more detailed description that ispresented later.

In accordance with one or more embodiments and corresponding disclosurethereof, various aspects are described in connection with facilitatingsearching for a cell (e.g., base station) in a communication system.More particularly, exemplary systems and methodologies are describedthat facilitate searches for a cell in a wireless communicationenvironment. For example, a mobile device can employ a searcher that candetect timing information respectively associated with PSCs and cells todetermine the cell with the highest correlation. The searcher can detectSSCs, which can include detecting associated phase information, todetermine the SSC with the highest correlation, CP length, and/or otherinformation to facilitate identifying a desired cell having thestrongest signal to establish communication between the mobile deviceand the desired cell. PSCs respectively associated with cells can havedifferent positions in the symbol sequences, and SSCs can respectivelybe phase shifted at different angles to facilitate detection andidentification of a cell(s), where a PSC can be utilized as a phasereference by the associated SSC.

According to an aspect, a method that facilitates a multi-stage cellsearch, comprises: detecting timing information related to primarysynchronization channels (PSCs); and identifying a cell based in part onphase information associated with a SSC.

Another aspect provides for a computer readable medium having storedthereon computer executable instructions for carrying out the followingacts: detecting timing information related to primary synchronizationchannels (PSCs); and identifying a cell based in part on phaseinformation associated with a SSC.

Yet still another aspect provides for an apparatus operable in wirelesscommunication system, the apparatus comprising: means for detectingtiming information related to primary synchronization channels (PSCs);and means for identifying a cell based in part on phase informationassociated with a SSC.

Still yet another aspect provides for an apparatus operable in awireless communication system that comprises a processor, configured to:detect timing information related to primary synchronization channels(PSCs); and identify a cell based in part on phase informationassociated with a SSC; and a memory coupled to the processor for storingdata.

To the accomplishment of the foregoing and related ends, the one or moreembodiments comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative aspects ofthe one or more embodiments. These aspects are indicative, however, ofbut a few of the various ways in which the principles of variousembodiments can be employed and the described embodiments are intendedto include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a wireless communication system inaccordance with various aspects set forth herein.

FIGS. 2A-2F are illustrations of example radio frames that can beassociated with respective base stations within a wireless communicationenvironment.

FIGS. 3A-3F are illustrations of other example radio frames that can beassociated with respective base stations within a wireless communicationenvironment.

FIGS. 4A-4F are illustrations of still other example radio frames thatcan be associated with respective base stations within a wirelesscommunication environment.

FIG. 5 is a depiction of an example system that can facilitate cellsearches within a wireless communication environment.

FIG. 6 is an illustration of an example system that can generateinformation to facilitate cell searches within a wireless communicationenvironment.

FIG. 7 is an illustration of an example methodology that can facilitatesearching for cells within a wireless communication environment.

FIG. 8 is an illustration of another example methodology that canfacilitate searching for cells within a wireless communicationenvironment.

FIG. 9 is a depiction of an example mobile device that can facilitateperformance of searches for base stations in a wireless communicationsystem.

FIG. 10 is an illustration of an example system that can generateinformation to facilitate searches for base stations associated with awireless communication environment.

FIG. 11 is an illustration of an example wireless network environmentthat can be employed in conjunction with the various systems and methodsdescribed herein.

FIG. 12 is an illustration of an example system that can facilitatesearching for base stations in a wireless communication environment.

FIG. 13 is a depiction of another example system that can facilitatesearching for base stations in a wireless communication environment.

FIG. 14 is a depiction of another example system that can facilitatesearching for base stations in a wireless communication environment.

DETAILED DESCRIPTION

Various embodiments are now described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of one or more embodiments. It may be evident, however,that such embodiment(s) may be practiced without these specific details.In other instances, well-known structures and devices are shown in blockdiagram form in order to facilitate describing one or more embodiments.

As used in this application, the terms “component,” “module,” “system,”and the like are intended to refer to a computer-related entity, eitherhardware, firmware, a combination of hardware and software, software, orsoftware in execution. For example, a component can be, but is notlimited to being, a process running on a processor, a processor, anobject, an executable, a thread of execution, a program, and/or acomputer. By way of illustration, both an application running on acomputing device and the computing device can be a component. One ormore components can reside within a process and/or thread of executionand a component can be localized on one computer and/or distributedbetween two or more computers. In addition, these components can executefrom various computer readable media having various data structuresstored thereon. The components can communicate by way of local and/orremote processes such as in accordance with a signal having one or moredata packets (e.g., data from one component interacting with anothercomponent in a local system, distributed system, and/or across a networksuch as the Internet with other systems by way of the signal).

Furthermore, various embodiments are described herein in connection witha mobile device. A mobile device can also be called a system, subscriberunit, subscriber station, mobile station, mobile, remote station, remoteterminal, access terminal, user terminal, terminal, wirelesscommunication device, user agent, user device, or user equipment (UE). Amobile device can be a cellular telephone, a cordless telephone, aSession Initiation Protocol (SIP) phone, a wireless local loop (WLL)station, a personal digital assistant (PDA), a handheld device havingwireless connection capability, computing device, or other processingdevice connected to a wireless modem. Moreover, various embodiments aredescribed herein in connection with a base station. A base station canbe utilized for communicating with mobile device(s) and can also bereferred to as an access point, Node B, or some other terminology.

Moreover, various aspects or features described herein can beimplemented as a method, apparatus, or article of manufacture usingstandard programming and/or engineering techniques. The term “article ofmanufacture” as used herein is intended to encompass a computer programaccessible from any computer-readable device, carrier, or media. Forexample, computer-readable media can include but are not limited tomagnetic storage devices (e.g., hard disk, floppy disk, magnetic strips,etc.), optical disks (e.g., compact disk (CD), digital versatile disk(DVD), etc.), smart cards, and flash memory devices (e.g., EPROM, card,stick, key drive, etc.). Additionally, various storage media describedherein can represent one or more devices and/or other machine-readablemedia for storing information. The term “machine-readable medium” caninclude, without being limited to, wireless channels and various othermedia capable of storing, containing, and/or carrying instruction(s)and/or data.

Referring now to FIG. 1, a wireless communication system 100 isillustrated in accordance with various embodiments presented herein.System 100 comprises a plurality of base stations 102 (only one basestation 102 is depicted in FIG. 1 for clarity and brevity) that can eachinclude multiple antenna groups. For example, one antenna group caninclude antennas 104 and 106, another group can comprise antennas 108and 110, and an additional group can include antennas 112 and 114. Twoantennas are illustrated for each antenna group; however, more or fewerantennas can be utilized for each group. Base station 102 canadditionally include a transmitter chain and a receiver chain, each ofwhich can in turn comprise a plurality of components associated withsignal transmission and reception (e.g., processors, modulators,multiplexers, demodulators, demultiplexers, antennas, etc.), as will beappreciated by one skilled in the art.

Each base station 102 can communicate with one or more mobile devicessuch as mobile device 116 and mobile device 122; however, it is to beappreciated that a base station 102 can communicate with substantiallyany number of mobile devices similar to mobile devices 116 and 122.Mobile devices 116 and 122 can be, for example, cellular phones, smartphones, laptops, handheld communication devices, handheld computingdevices, satellite radios, global positioning systems, PDAs, and/or anyother suitable device for communicating over wireless communicationsystem 100. As depicted, mobile device 116 is in communication withantennas 112 and 114, where antennas 112 and 114 transmit information tomobile device 116 over a forward link 118 and receive information frommobile device 116 over a reverse link 120. Moreover, mobile device 122is in communication with antennas 104 and 106, where antennas 104 and106 transmit information to mobile device 122 over a forward link 124and receive information from mobile device 122 over a reverse link 126.In a frequency division duplex (FDD) system, forward link 118 canutilize a different frequency band than that used by reverse link 120,and forward link 124 can employ a different frequency band than thatemployed by reverse link 126, for example. Further, in a time divisionduplex (TDD) system, forward link 118 and reverse link 120 can utilize acommon frequency band and forward link 124 and reverse link 126 canutilize a common frequency band.

Each group of antennas and/or the area in which they are designated tocommunicate can be referred to as a sector of base station 102. Forexample, antenna groups can be designed to communicate to mobile devicesin a sector of the areas covered by base station 102. In communicationover forward links 118 and 124, the transmitting antennas of basestation 102 can utilize beamforming to improve signal-to-noise ratio offorward links 118 and 124 for mobile devices 116 and 122. Also, whilebase station 102 utilizes beamforming to transmit to mobile devices 116and 122 scattered randomly through an associated coverage, mobiledevices in neighboring cells can be subject to less interference ascompared to a base station transmitting through a single antenna to allits mobile devices.

In accordance with an aspect, a mobile device 116 can search for adesired base station 102 in the wireless communication environment(e.g., employing Orthogonal Frequency Division Multiplexing (OFDM) tofacilitate system access), in order to locate, identify, and/orestablish communications with the desired base station 102, so that themobile device 116 can communicate (e.g., transmit data, receive data) inthe wireless communication environment. For instance, a desired basestation 102 can be a base station that provides the best (e.g.,strongest) signal for communication. In order to communicate with a basestation 102, the mobile device 116 synchronizes itself with the basestation 102. To facilitate searching for and synchronizing to a desiredbase station 102, the mobile device 116 can receive and/or detectrespective Primary Synchronization Channels (PSCs) and respectiveSecondary Synchronization Channels (SSCs) from respective base stations102. The mobile device 116 can detect, analyze, and/or evaluate thereceived PSCs and SSCs to facilitate identifying and/or selecting adesired base station 102 in order to establish communications with suchbase station 102. The PSC from base stations can be a known signal withrespect to the mobile device 116, and there can be a common PSC, or arelatively small number of PSCs, as to the base stations 102 in anetwork. The PSC can also provide the mobile device 116 with timinginformation that can be utilized to facilitate synchronization of themobile device 116 with a base station 102. SSCs can be unique torespective base stations 102, and can facilitate identifying aparticular base station 102 (e.g., the SSCs can include base stationidentification information, antenna information associated with a basestation, etc.), where there can be a plurality of different SSCs. Forinstance, a SSC can be associated with a respective hypotheses, wherethere can be a plurality of different hypotheses. The mobile device 116can detect and identify which SSC sequence has been transmitted from aparticular cell (e.g. base station 102) and thereby the hypotheses canbe known for that cell, as well as the identification of the cell.

Conventionally, in certain communication systems, such as OFDM systems,if each base station are transmitting the same PSC signal, a mobiledevice may not be able to differentiate between base stations todetermine how many base stations and/or which base stations aretransmitting respective signals, and this can inhibit and/or prevent amobile device from identifying a desired base station when attempting tosearch for and identify a base station in order to establishcommunication.

In accordance with various aspects and embodiments, the subjectinnovation can facilitate shifting the PSC location for different basestations 102 so that the PSC transmit timing can be different fordifferent base stations 102. As a result, the mobile device 116 candifferentiate between disparate base stations 102 in the network inorder to quickly and efficiently search for and identify a desired basestation 102 (e.g., base station with strongest signal).

In one aspect, the mobile device 116 can search for a base station 102where the cyclic prefix (CP) can be detected blindly. In such instance,the distance (e.g., relative timing distance) between two consecutivePSCs can be the same for both a long CP and a short CP, and can befixed. For example, the distance D1 can be 5 ms. In accordance with anaspect, the SSCs respectively generated by base stations 102 can utilizeChu sequences with different bases or different cyclic shifts (e.g.,different sequences). To facilitate searches, an additional phase shiftof e^(jkθ) can be applied to the SSCs, where k=0, 1, 2, . . . , M−1, andθ=2π/M. M can relate to the number of different phases that can beemployed, where, for example, a different phase shift can be applied toSSCs in each different base station 102 in the network. There is nophase applied to the PSC when the PSC is transmitted. When a SSC istransmitted, there is a phase shift (e.g., phase rotation) applied tothe SSC, where the phase angle for the phase shift can be based in parton the PSC sequence.

The mobile device 116 can detect the respective phase shift of a SSCwith respect to its associated PSC, and that phase shift can representinformation that can be utilized by the mobile device 116 to facilitateidentifying a particular base station 102.

In accordance with another aspect, SSC1 and SSC2 can have differentcombinations of phase shift, such as e^(jkθ) and e^(jmθ), for example,where k=0, 1, 2, . . . , M−1, and m=0, 1, 2, . . . , M−1, which canresult in M*M potential combinations. In accordance with still anotheraspect, SSC1 and SSC2 can have the same phase shift e^(jkθ). In suchinstance, there can be improved phase detection probability. Also, therecan be at least three potential combinations, for instance, that canrepresent antenna information (e.g., 1, 2, or 4 antennas) associatedwith a base station 102, and the phase information detected by themobile device 116 can facilitate determining the number of antennasassociated with such base station 102, as there can be a unique mappingbetween the number of phases (e.g., phase shift key (PSK)) and thenumber of antennas used by the base station 102. Accordingly, at leastthree groups (e.g., α, β, γ) can be represented by using a combinationof SSC order in a radio frame and the phase modulation on top of SSCs.

The phase shift information associated with a SSC also can be utilizedby a mobile device 116 to facilitate determining the location (e.g.,position) of the associated PSC in the symbol sequence. For instance,the mobile device 116 can perform timing detection based in part on thedetected PSC, which can be a correlation between the peak and the PSCsequence, and the mobile device 116 can utilize the phase informationrelated to the SSC associated with the PSC to facilitate determining thebase station 102 that transmitted such peak. By identifying the phase ofthe associated SSC, the mobile device 116 can determine which basestation 102 is transmitting the PSC.

In one aspect, the CP length can be detected blindly after symbol timingdetection.

In an aspect, the number of additional hypotheses carried by SSC and thereference signal can be flexible. For example, 64 hypotheses from twoSSCs and 8 hypotheses from the reference signal can yield a total of 512hypotheses. As another example, 512 hypotheses from the SSCs and thereference signal utilized for validation can result in a total of 512hypotheses. It is to be understood and appreciated that the referencesignal can be placed at the 0^(th) and 5^(th) symbols for both the longCP and short CP instances. It is also to be understood and appreciatedthat it is not necessary for the reference signal to be transmittedwithin the frequency band where PSC and SSC are transmitted, as the PSCand SSC can be utilized as a reference signal.

Turning briefly to FIGS. 2A-2F, illustrated is an example of radioframes 200, 202, 204, 206, 208, 210, respectively, that can berepresentative of radio frames respectively associated with differentbase stations 102 in a network. For instance, referring to radio frame200, there can be a preamble (P) that can be a sub-frame of the radioframe. The PSCs and SSCs are typically only sent during the preamble (P)and the mid-amble (M). As depicted in radio frames 200, 202, and 204,the distance between PSCs can be fixed. For instance, the distance canbe 5 ms. A SSC, such as SSC1 and SSC2, can be next to each PSC,respectively, in the sets of symbols. However, as depicted in radioframes, 200, 202, and 204, the position in the respective symbolsequences can be different, where, for instance, PSC can be in position4 in the symbol sequence with respect to radio frame 200, PSC can be inposition 3 with respect to radio frame 202, and PSC can be in position 2of the symbol sequence with respect to radio frame 204.

A base station 102 can contain 3 sectors, for example, and each sectorcan utilize one of those radio frames 200, 202, 204 (e.g., can utilizethe timing of the respective radio frames 200, 202, 204). For instance,a sector 0 can utilize radio frame 200, a sector 1 can utilize radioframe 202, and a sector 2 can utilize radio frame 204. Even though thesectors are part of the same base station 102, when the respectivesectors transmit their PSCs, the respective PSCs are not overlapping,because each PSC can occupy a different position in terms of time. Themobile station 116 can detect each of the three different PSCs.

Conventionally, the PSCs would each occupy the same position in thesequence, and as a result, a mobile station effectively would only seeone PSC, and could not differentiate between disparate PSCs, because allthe PSCs would arrive to the mobile station at the same time.

With regard again to radio frames 200, 202, and 204, for each PSC therecan be a SSC associated therewith. To facilitate detecting the phasereference of a SSC, the PSC can be utilized as a phase reference. EachSSC of the radio frames 200, 202, 204, can have a different phasereference because each PSC occupies different positions in the symbolsequence, so the channel between the base station 102 and the mobiledevice 116 for each PSC can be different. Once a respective channel isapplied to a SSC, unique channel information can be observed.

Conventionally, where the PSCs occupy the same location in the symbolsequence, the channels can overlap and the unique channel informationcannot be observed. As a result, identifying a desired base station canbe inhibited and/or prevented.

Referring again to radio frames 200, 202, and 204, for example,different base stations 102 can be transmitting different PSC sequenceswith different phase shifts for respective SSCs respectively associatedwith the PSCs. The mobile device 116 can detect the PSC with thestrongest correlation (e.g., highest peak, strongest signal). The mobilestation 116 can detect information related to the SSCs, such as phaseshift information, that are associated with the strongest signal tofacilitate determining the base station 102 that transmitted thestrongest signal. The mobile station 116 can evaluate the informationassociated with such SSCs to identify the base station 102 thattransmitted the strongest signal, and can establish communications withthat base station 102.

With regard to FIGS. 2D-2F and corresponding radio frames 206, 208, and210, such radio frames depict a long CP. For each group α, β, γ, therespective PSCs can have a location in the symbol sequence that can beunique to the group in which a respective PSC belongs to facilitatedifferentiating between PSCs, similar to that of the radio frames 200,202, 204 of the short CP. Also, unique phase shifting of the respectiveSSCs for each group α, β, γ can be employed to facilitate providinginformation regarding respectively associated PSCs to facilitateidentifying a base station 102 that has the PSC with the strongestcorrelation.

As the CP can be unknown to the mobile device 116, during detection, themobile device 116 also can perform blind CP detection to facilitatedetermining the CP. For instance, when the mobile device 116 hasdetected a desired signal from detecting the PSC, and has detectedadditional information, such as phase reference information related toSSCs, the mobile device 116 can detect (e.g., test the hypotheses) thesignal strengths of SSCs respectively associated with a long CP and ashort CP that can each have the same phase shift (e.g., group β withlong CP, and group β with short CP), for instance. The mobile device 116can compare the respective signal strengths (e.g., correlation values)of the respective SCCs to determine the particular group that has thehighest correlation value, which can be the group (e.g., base station102) having the strongest signal, and can be the desired base station102, and the CP also can be determined as a result.

The respective relative timing and respective phase shifts for SSCs ofthe respective radio frames 200, 202, 204, 206, 208, 210 is provided inTable 1, where in Table 1, provided is an example where the same phaseshift can be used for both SSCs, where M=3 (e.g., 3-Phase Shift Key(PSK)):

TABLE 1 Relative timing Phase Shift Phase Shift between 2 PSCs for SSC1for SSC2 Group α: short CP D1 ms θ = 0 θ = 0 Group β: short CP D1 ms$\theta = \frac{2\pi}{3}$ $\theta = \frac{2\pi}{3}$ Group γ: short CP D1ms $\theta = \frac{4\pi}{3}$ $\theta = \frac{4\pi}{3}$ Group α: long CPD1 ms θ = 0 θ = 0 Group β: long CP D1 ms $\theta = \frac{2\pi}{3}$$\theta = \frac{2\pi}{3}$ Group γ: long CP D1 ms$\theta = \frac{4\pi}{3}$ $\theta = \frac{4\pi}{3}$

For instance, the mobile device 116 can determine that the group β withshort CP has the strongest correlation based in part on the detection ofthe PSCs, and the location of the PSCs in the symbol sequences canfacilitate providing a unique phase reference for a SSC with respect toan associated PSC when the mobile station 116 detects the SSCsassociated with the PSCs. The mobile device 116 can detect the phaseshift of the respective SSCs, SSC1 and SSC2, which, in this example, caneach be θ=2π/3, and, since the mobile device 116 does not yet knowwhether the strong signal (e.g., highest peak) is associated with ashort CP or a long CP, the mobile device 116 can perform blind CPdetection and can test the respective hypotheses of both the group βhaving short CP and group β having long CP, where the signal of the SSCfor group β having short CP and the signal of the SSC for group β havinglong each can be detected and compared with each other to facilitatedetermining which of the respective SSCs has a stronger signal (e.g.,higher correlation), as the signal of the SSC for the short CP can havea different value than the signal of the SSC for the long CP. As aresult, the proper CP can be determined, which can facilitateidentifying the desired base station 102 (e.g., the desired group in theexample). Based in part on the detections and evaluations by the mobiledevice 116, the mobile device 116 can determine that the PSC with thestrongest correlation is associated with group β with short CP. Themobile station 116 has thereby identified the desired base station 102and can establish communications with that base station 102.

Referring again to FIG. 1, in yet another aspect, there can be analternative hybrid approach to facilitate searching for a desired basestation 102 in a wireless communication environment. The mobile device116 can search for and identify a desired base station 102, where thedistance (e.g., relative timing distances) between two consecutive PSCsassociated with a short CP can be different from the distance betweentwo consecutive PSCs associated with a long CP, although the CP lengthfor each group (e.g., long CP group of α, β, γ, short CP of α, β, γ) canbe the same distance (e.g. short CP group can have timing distance ofD1, long CP group can have relative timing distance of D1+D2). CP lengthcan be detected by testing the two different distances between twoconsecutive PSCs. This hybrid approach can be more efficient since thesum power of two time aligned PSC symbols despread by PSC sequence canbe compared with the sum power of two random OFDM symbols despread byPSC sequence. The relative distance of any two consecutive PSCs can befixed. For instance, D1 can be the relative distance of the short CP,and D2 can be the relative distance for the long CP, where, for example,D1 can be 5 ms and D2 can be 83 μs.

In accordance with an aspect, the SSCs respectively generated by basestations 102 can utilize Chu sequences with different bases or differentcyclic shifts. To facilitate searches, an additional phase shift ofe^(jkθ) can be applied to the SSC, where k=0, 1, 2, . . . , M−1 andθ=2π/M.

In accordance with another aspect, SSC1 and SSC2 can have differentcombinations of phase shift, such as e^(jkθ) and e^(jmθ), for example,where k=0, 1, 2, . . . , M−1, and m=0, 1, 2, . . . , M−1, which canresult in M*M potential combinations. In accordance with still anotheraspect, SSC1 and SSC2 can have the same phase shift e^(jkθ). In suchinstance, there can be improved phase detection probability. Also, therecan be at least three potential combinations, for instance, that canrepresent antenna information (e.g., 1, 2, or 4 antennas) associatedwith a base station 102. Accordingly, at least three groups (e.g., α, β,γ) can be represented by using a combination of SSC order in a radioframe and the phase modulation on top of SSCs.

In an aspect, the number of additional hypotheses carried by SSC and thereference signal can be flexible. For example, 64 hypotheses from twoSSCs and 8 hypotheses from the reference signal can yield a total of 512hypotheses. As another example, 512 hypotheses from the SSCs and thereference signal utilized for validation can result in a total of 512hypotheses. It is to be understood and appreciated that the referencesignal can be placed at the 0^(th) and 5^(th) symbols for both the longCP and short CP instances.

Turning briefly to FIGS. 3A-3F, illustrated is an example of radioframes 300, 302, 304, 306, 308, 310, respectively, that can berepresentative of radio frames respectively associated with differentbase stations 102 in a network. The respective relative timing andrespective phase shifts for SSCs of the respective radio frames 300,302, 304, 306, 308, 310 is provided in Table 2, where in Table 2,provided is an example of using the same phase shift for both SSCs,where M=3 (e.g., 3-PSK) is used:

TABLE 2 Relative timing Phase Shift Phase Shift between 2 PSCs for SSC1for SSC2 Group α: short CP D1 ms θ = 0 θ = 0 Group β: short CP D1 ms$\theta = \frac{2\pi}{3}$ $\theta = \frac{2\pi}{3}$ Group γ: short CP D1ms $\theta = \frac{4\pi}{3}$ $\theta = \frac{4\pi}{3}$ Group α: long CPD1 ms + D2 μs θ = 0 θ = 0 Group β: long CP D1 ms + D2 μs$\theta = \frac{2\pi}{3}$ $\theta = \frac{2\pi}{3}$ Group γ: long CP D1ms + D2 μs $\theta = \frac{4\pi}{3}$ $\theta = \frac{4\pi}{3}$

With regard to FIGS. 3A-3C and corresponding radio frames 300, 302, and304, such radio frames have a short CP. With regard to FIGS. 3D-3F andcorresponding radio frames, 306, 308, and 310, such radio frames have along CP. As depicted in Table 2, the radio frames associated with theshort CP can have the same relative distance with respect to each other,and the radio frames associated with the long CP can have the samerelative distance with respect to each other, but such relative distancecan be different (e.g., greater) than the relative distance of the radioframes having a short CP. The respective distance information of theshort CP and long CP can be utilized to facilitate determining the CPduring detection (e.g., timing detection). For each group α, β, γ of therespective CPs, the respective PSCs can have a location in the symbolsequence that can be unique to the group in which a respective PSCbelongs to facilitate differentiating between PSCs, similar to that ofthe radio frames 200, 202, 204 of the short CP, and radio frames 206,208, and 210 of the long CP of FIGS. 2A-2F, as described herein. Also,unique phase shifting of the respective SSCs for each group α, β, γassociated with a respective CP can be employed to facilitate providinginformation regarding respectively associated PSCs to facilitateidentifying a base station 102 that has the PSC with the strongestcorrelation.

The CP length can be determined by comparing the correlation resultsassociated with the timing detection, where, for instance, the PSCtiming detection yielding the highest result can be associated with thedesired CP and the CP length can be determined by the relative distanceassociated with the desired CP. For instance, with regard to FIGS.3A-3F, if a mobile device 116 performs a first timing detection with arelative distance of 5 ms and that yields a first result (e.g.,correlation value), and a second timing detection is performed with arelative distance of 5 ms+83 μs which yields a second result that ishigher than the first result, the mobile device 116 can determine thatthe CP associated with the second result is the desired CP (e.g.associated with the desired base station 102), and based in part on therelative distance, the mobile device 116 can determine that it is a longCP, as the long CP has the longer relative distance, as illustrated inFIGS. 3A-3F, for example.

Referring once again to FIG. 1, in accordance with yet another aspect ofthe disclosed subject matter, the mobile device 116 can employ anothertechnique to facilitate searching for and identifying the desired basestation 102 in the network. Such technique can be utilized by the mobilestation 116, for instance, when the SSC is placed in differentdirections for different groups such that the reference symbol positioncan be flexible. In such instances, there potentially can be an increasein the hypotheses that the mobile device 116 tests in order to identifythe desired base station 102.

Referring briefly to FIGS. 4A-4F, depicted is an example of radio frames400, 402, 404, 406, 408, 410, respectively, that can be representativeof radio frames respectively associated with different base stations 102in a network. With regard to FIGS. 4A-4C and corresponding radio frames400, 402, and 404, such radio frames have a short CP. With regard toFIGS. 4D-4F and corresponding radio frames, 406, 408, and 410, suchradio frames have a long CP. As an example, for the short CP (e.g.,radio frames 400, 402, 404), the 0^(th) and the 4^(th) symbols cancontain a reference signal, and for the long CP (e.g., radio frames 406,408, 410), the 0^(th) and the 3^(rd) symbols can contain a referencesignal.

As depicted in FIGS. 4A-4F, the SSCs can be positioned to the left orthe right of the associated PSC in the symbol sequence, which canfacilitate allowing flexibility with regard to the positioning of areference signal. The mobile device 116 can detect the respective timing(e.g., determine symbol timing) associated with PSCs respectivelyassociated with base stations 102 to detect the highest correlationvalue. To facilitate detecting the position of the SSC, once the timingassociated with a particular PSC is detected, the mobile device 116 cantest the hypotheses on the symbol positions on both the left and theright of the particular PSC, and can compare the results of the twohypotheses, where the hypotheses having the highest correlation resultcan be the position of the SSC associated with the particular PSC. Themobile device 116 can utilize the timing information and the informationassociated with the detected SSC (e.g., phase information) to facilitateidentifying the desired base station 102 in the network.

With reference to FIG. 5, illustrated is a system 500 that canfacilitate searches for a cell (e.g., base station) within a wirelesscommunication environment. System 500 can include a base station 102that can communicate with one or more mobile devices, such as mobiledevice 116. It is to be appreciated and understood that only one mobiledevice is depicted in FIG. 5 for clarity and brevity. Moreover, basestation 102 can communicate with other base station(s) and/or anydisparate devices (e.g., servers) (not shown) that can perform variousfunctions. The base station 102 (e.g., cell) and mobile device 116 eachcan be respectively the same or similar as, and/or can compriserespectively the same or similar functionality as, respective componentsas more fully described herein, such as, for example, with regard tosystem 100.

Mobile device 116 can search for a base station 102 (e.g., cell) among aplurality of base stations in a wireless communication environment inorder to establish communication with the base station 102 and othermobile devices (e.g. 122) in the wireless communication environment. Inone aspect, to facilitate searching for a base station 102, the mobiledevice 116 can comprise a searcher 502 that can search for and detectsignals provided by respective base stations (e.g., 102) to identifyand/or locate a desired base station 102 with which to establishcommunication.

The searcher 502 can include a PSC detector 504 that can detect timinginformation (e.g., symbol timing) associated with respective PSCstransmitted by respective base stations (e.g., 102), where the timinginformation of respective PSCs can be analyzed and evaluated tofacilitate determining the respective strengths of such PSCs, forinstance. The PSC detector 504 can evaluate respective signal strengthsand can perform calculations to determine respective correlation valuesassociated with respective PSCs in order to identify the PSC having thehighest correlation value, where such PSC can be associated with thedesired base station 102 for which the searcher 502 is searching. ThePSC detector 504 can also measure and/or evaluate relative distancesrespectively associated with PSCs, where such distance information canbe utilized to facilitate determining CP lengths and/or identifying abase station 102.

The searcher 502 can further include a SSC detector 506 that can detectinformation associated with SSCs transmitted by respective base stations(e.g., 102), where the SSCs can be analyzed and evaluated to facilitatedetermining the respective phase angles between PSCs and respectivelyassociated SSCs, identifying a particular base station 102, and/orfacilitating establishing a connection between the mobile device 116 anda base station (e.g., 102), for example. The SSC detector 506 can detectphase shift information and/or other information to facilitatedetermining the base station 102 that is transmitting the PSC detectedby the PSC detector 504. The SSC detector 506 can also evaluate thedetected information to facilitate determining the number of antennasassociated with a particular base station 102. The SSC detector 506 canevaluate and/or perform calculations with regard to the detectedinformation associated with respective SSCs to determine the particularSSC that has the highest correlation value, where such SSC can beassociated with the base station 102 for which the searcher 502 issearching.

In one aspect, the SSC detector 506 can be utilized to test hypothesesto facilitate detecting (e.g. blind detection) of a CP length, whenSSC(s) associated with the short CP has the same phase shift as theSSC(s) associated with the long CP. The SSC detector 506 can evaluateand perform calculations to determine which SSC has the highestcorrelation value and can determine the CP length associated with thedesired base station 102 based in part the on the SSC having the highestcorrelation value. The SSC detector 506 also can be utilized to testhypotheses to facilitate detecting the desired SSC when the SSC can belocated on either side of an associated PSC in the symbol sequence. TheSSC detector 506 can evaluate and perform calculations to determinewhich SSC has the highest correlation value and can determine theposition of the SSC with respect to the associated PSC in the symbolsequence based in part the on the SSC having the highest correlationvalue. The SSC having the highest value can be the desired SSC and canbe associated with the desired base station 102. Information, such asphase information, associated with the desired SSC can be evaluated tofacilitate identifying the desired base station 102.

Now referring to FIG. 6, illustrated is a system 600 that facilitatesearches for a cell within a wireless communication environment. System600 can include a plurality of base stations 102 (only one base station102 is depicted in FIG. 6 for clarity and brevity) that can communicatewith one or more mobile devices, such as mobile device 116, in awireless communication environment. It is to be appreciated andunderstood that only one mobile device 116 is depicted in FIG. 6 forclarity and brevity. Moreover, base station 102 can communicate withother base station(s) and/or any disparate devices (e.g., servers) (notshown) that can perform various functions, as desired. The base station102 and mobile device 116 each can be respectively the same or similaras, and/or can comprise respectively the same or similar functionalityas, respective components as more fully described herein, such as, forexample, with regard to system 100 and/or system 500.

Each base station 102 can include a PSC generator 602 that canfacilitate generating and providing a PSC that can be transmitted in thewireless communication environment. The PSC can be utilized tofacilitate searches by a mobile device 116 to locate, identify, and/orestablish communication with a base station (e.g., 102) in the wirelesscommunication environment (e.g., network). The PSC that is generated canbe common to base stations 102 in the network or there can be more thanone PSC with respective values that can be respectively employed by thebase stations 102.

Each base station 102 can also include a SSC generator 604 that cangenerate and provide a SSC (e.g., each base station can generate aunique SSC) that can be transmitted (e.g., broadcast) in a wirelesscommunication environment. A SSC can facilitate cell searches, as themobile device 116 can detect information associated with a SSC, and theSSC along with the PSC can be utilized to facilitate searches for adesired base station 102 in the wireless communication environment andestablishing communication with such base station 102.

Further, each base station 102 can also include a reference signalgenerator 606 that can generate and provide reference signals. Thereference signals can be detected utilized, as desired, by the mobiledevice 116 to facilitate detecting the timing related to PSCs and/orfacilitate identifying a desired base station 102.

Referring to FIGS. 7-8, methodologies relating to utilizing pilot(s) toenable inter-technology handoffs in a wireless communication environmentare illustrated. While, for purposes of simplicity of explanation, themethodologies are shown and described as a series of acts, it is to beunderstood and appreciated that the methodologies are not limited by theorder of acts, as some acts can, in accordance with one or moreembodiments, occur in different orders and/or concurrently with otheracts from that shown and described herein. For example, those skilled inthe art will understand and appreciate that a methodology couldalternatively be represented as a series of interrelated states orevents, such as in a state diagram. Moreover, not all illustrated actscan be required to implement a methodology in accordance with one ormore embodiments.

With reference to FIG. 7, illustrated is a methodology 700 that canfacilitate searching for a cell (e.g., base station 102) in a wirelesscommunication environment. At 702, timing information can be detected.In one aspect, timing information can be respectively associated withPSCs, which can respectively be associated with cells in a network. Amobile device 116 can utilize a searcher (e.g., 502) that can detecttiming information respectively associated with PSCs and associatedcells. The searcher can evaluate received information and can performcalculations to facilitate detecting and/or determining timinginformation, which can be utilized to facilitate locating a desiredcell.

At 704, a cell can be identified based in part on phase information of aSSC associated with the PSC. In one aspect, the searcher can detectSSCs, and information associated therewith, such as phase information,which can be utilized to determine which SSC has the highestcorrelation, identifying a desired cell, and/or detecting a CP, forinstance. The searcher can evaluate received information, such asinformation associated with SSCs and/or PSCs, to facilitate detectingSSCs, identifying cells, and/or detecting CPs. Information regarding thelocation of a PSC in a symbol sequence and/or phase information of aSSC, where the PSC can be utilized as a phase reference with respect tothe associated SSC, can be utilized by the searcher in makingdeterminations and/or identifications with respect to a desired cell.

Turning to FIG. 8, illustrated is a methodology 800 that can facilitatesearching for cells in a wireless communication environment. At 802,correlation values respectively associated with PSCs can be determined.In one aspect, a mobile device (e.g. 116) can employ a searcher (e.g.,502) that can determine and/or calculate correlation values associatedwith respective PSCs to determine the PSC with the highest correlationvalue. The PSC with the highest correlation value can be associated witha desired cell (e.g., a desired base station 102) with which the mobiledevice desires to identify and establish communication. The correlationvalues can correspond to the timing information respectively associatedwith PSCs.

At 804, correlation values respectively associated with SSCs can bedetermined. In one aspect, the searcher can determine and/or calculatecorrelation values associated with respective SSCs, where the searchercan determine which SSC has the highest correlation value. The SSC withthe highest correlation value can be associated with the desired cell.Phase information associated with the SSCs can be utilized to facilitatedetecting the desired SSC. At 806, a CP length can be detected. In oneaspect, where the CP length is unknown but the relative timing distancebetween two PSCs in a radio frame is fixed, the searcher can employblind CP detection to facilitate detecting the CP length. In anotheraspect, when the relative distance between two consecutive PSCs relatedto a short CP is different from the relative distance between twoconsecutive PSCs related to a long CP, the searcher can detect and/ordetermine the CP length by calculating correlation values at differentrelative distances, where the relative distance associated with thehighest correlation value can be associated with the CP length that isdesired to be detected.

At 808, a cell can be selected based in part on the correlation values.In one aspect, the searcher can determine the PSC that is associatedwith the highest correlation value as compared to other PSCs, the SSCthe is associated with a highest correlation value as compared to otherSSCs, and/or the CP length that is associated with a highest correlationvalue as compared to other CP lengths, to facilitate selecting a cell,which can be the desired base station (e.g., base station having thestrongest signal) with which the mobile device can desire to establishcommunication.

It will be appreciated that, in accordance with one or more aspectsdescribed herein, inferences can be made regarding searching for basestations (e.g. cells) by a mobile device in a wireless communicationenvironment. As used herein, the term to “infer” or “inference” refersgenerally to the process of reasoning about or inferring states of thesystem, environment, and/or user from a set of observations as capturedvia events and/or data. Inference can be employed to identify a specificcontext or action, or can generate a probability distribution overstates, for example. The inference can be probabilistic—that is, thecomputation of a probability distribution over states of interest basedon a consideration of data and events. Inference can also refer totechniques employed for composing higher-level events from a set ofevents and/or data. Such inference results in the construction of newevents or actions from a set of observed events and/or stored eventdata, whether or not the events are correlated in close temporalproximity, and whether the events and data come from one or severalevent and data sources.

According to an example, one or more methods presented above can includemaking inferences pertaining to detecting a PSC, detecting a SSC,determining a relative strength of a PSC or other signal, etc. It willbe appreciated that the foregoing examples are illustrative in natureand are not intended to limit the number of inferences that can be madeor the manner in which such inferences are made in conjunction with thevarious embodiments and/or methods described herein.

FIG. 9 is an illustration of a mobile device 900 that can facilitateperforming searches for base stations in a wireless communicationsystem. Mobile device 900 comprises a receiver 902 that receives asignal from, for instance, a receive antenna (not shown), and performstypical actions thereon (e.g., filters, amplifies, downconverts, etc.)the received signal and digitizes the conditioned signal to obtainsamples. Receiver 902 can be, for example, an MMSE receiver, and cancomprise a demodulator 904 that can demodulate received symbols andprovide them to a processor 906 for channel estimation. Processor 906can be a processor dedicated to analyzing information received byreceiver 902 and/or generating information for transmission by atransmitter 908, a processor that controls one or more components ofmobile device 900, and/or a processor that both analyzes informationreceived by receiver 902, generates information for transmission bytransmitter 908, and controls one or more components of mobile device900. Mobile device 900 can also comprise a modulator 910 that can workin conjunction with the transmitter 908 to facilitate transmittingsignals (e.g. data) to, for instance, a base station 102, another mobiledevice, etc.

Mobile device 900 can additionally comprise memory 912 that can beoperatively coupled to processor 906 and that can store data to betransmitted, received data, information related to PSCs associated withbase stations, information related to SSCs associated with respectivebase stations, information associated with correlation determinationsrelated to cell searches, information related to CP lengths, and/orother information that can facilitate performing searches for a desiredbase station 102 (e.g., cell) in a wireless communication environment.Memory 912 can additionally store protocols and/or algorithms associatedwith searching for base stations in a wireless communicationenvironment.

It will be appreciated that the memory 912 (e.g., data store) describedherein can comprise volatile memory and/or nonvolatile memory. By way ofillustration, and not limitation, nonvolatile memory can include readonly memory (ROM), programmable ROM (PROM), electrically programmableROM (EPROM), electrically erasable PROM (EEPROM), flash memory, and/ornonvolatile random access memory (NVRAM). Volatile memory can includerandom access memory (RAM), which can act as external cache memory. Byway of illustration and not limitation, RAM is available in many formssuch as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM(SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM),Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM). The memory 912of the subject systems and methods is intended to comprise, withoutbeing limited to, these and any other suitable types of memory.

The processor 906 can also comprise a searcher 502 that can facilitatesearches by the mobile device 900 to locate, identify, and/or establishcommunication with a desired base station (e.g. 102) amongst a pluralityof base stations in a wireless communication environment. It is to beappreciated and understood that the searcher 502 can be the same orsimilar as, or can comprise the same or similar functionality as,respective components such as more fully described herein, for example,with regard to system 100 and/or system 500. It is to be furtherappreciated and understood that the searcher 502 can be a stand-aloneunit (as depicted), can be contained within the processor 906, can beincorporated within another component, and/or virtually any suitablecombination thereof, as desired.

FIG. 10 is an illustration of a system 1000 that can facilitate searchesfor a base station associated with a wireless communication system.System 1000 can comprise a plurality of base stations 102 (e.g., accesspoint, . . . ) (only one base station is depicted in FIG. 10 for brevityand clarity), where each base station 102 can include a receiver 1002that can receive signal(s) from one or more mobile devices 116 through aplurality of receive antennas 1004, and a transmitter 1006 that cantransmit signals (e.g., data) to the one or more mobile devices 116through a transmit antenna 1008. Receiver 1002 can receive informationfrom receive antennas 1004 and can be operatively associated with ademodulator 1010 that can demodulate received information. Demodulatedsymbols can be analyzed by a processor 1012 that can be a processordedicated to analyzing information received by receiver 1002 and/orgenerating information for transmission by a transmitter 1006, aprocessor that controls one or more components of base station 102,and/or a processor that both analyzes information received by receiver1002, generates information for transmission by transmitter 1006, andcontrols one or more components of base station 102. The base station102 can also comprise a modulator 1014 that can work in conjunction withthe transmitter 1006 to facilitate transmitting signals (e.g., data) to,for instance, a mobile device 116, another device, etc.

Processor 1012 can be coupled to a memory 1016 that can storeinformation related to data to be transmitted, received data,information related to a PSC, information related to a SSC, and/or otherinformation relevant to searches by a mobile device 116 for a basestation (e.g. 102) in a wireless communication environment. Memory 1016can additionally store protocols and/or algorithms associated with andfacilitating providing PSCs and/or SSCs in order to facilitate searchesby a mobile device 116 for a base station 102 in the wirelesscommunication environment.

Processor 1012 can be coupled to a PSC generator 602 that can facilitategenerating and providing a PSC that can be transmitted in the wirelesscommunication environment. The PSC can be utilized to facilitatesearches by a mobile device 116 to locate, identify, and/or establishcommunication with the base station 102 in the wireless communicationenvironment. It is to be appreciated and understood that the PSCgenerator 602 can be the same or similar as, or can comprise the same orsimilar functionality as, respective components such as more fullydescribed herein, for example, with regard to system 100 and/or system600. It is to be further appreciated and understood that the PSCgenerator 602 can be a stand-alone unit (as depicted), can be includedwithin the processor 1012, can be incorporated within another component,and/or virtually any suitable combination thereof, as desired.

Processor 1012 can be coupled to a SSC generator 604 that can generateand provide a SSC (e.g., each base station can generate a unique SSC)that can be transmitted (e.g., broadcast) in a wireless communicationenvironment. A SSC can be detected by a mobile device 116, and the SSCalong with the PSC can be utilized to facilitate searches for a desiredbase station 102 in the wireless communication environment andestablishing communication with such base station 102. It is to beappreciated and understood that the SSC generator 604 can be the same orsimilar as, or can comprise the same or similar functionality as,respective components such as more fully described herein, for example,with regard to system 100 and/or system 600. It is to be furtherappreciated and understood that the SSC generator 604 can be can be astand-alone unit (as depicted), included within the processor 1012, canbe incorporated within another component, and/or virtually any suitablecombination thereof, as desired.

Processor 1012 can be and/or can be coupled to a reference signalgenerator 606 that can generate and provide reference signals, forexample, to mobile devices (e.g., 116) to facilitate timing detectionand/or facilitate identifying a desired base station 102 during searchesfor a desired base station 102 by a mobile device (e.g. 116). It is tobe appreciated and understood that the reference signal generator 606can be the same or similar as, or can comprise the same or similarfunctionality as, respective components such as more fully describedherein, for example, with regard to system 100 and/or system 600. It isto be further appreciated and understood that the reference signalgenerator 606 can be can be a stand-alone unit (as depicted), includedwithin the processor 1012, can be incorporated within another component,and/or virtually any suitable combination thereof, as desired

FIG. 11 shows an example wireless communication system 1100. Thewireless communication system 1100 depicts one base station 1110 and onemobile device 1150 for sake of brevity. However, it is to be appreciatedthat system 1100 can include more than one base station and/or more thanone mobile device, wherein additional base stations and/or mobiledevices can be substantially similar or different from example basestation 1110 and mobile device 1150 described below. In addition, it isto be appreciated that base station 1110 and/or mobile device 1150 canemploy the systems (FIGS. 1, 5-6, and 9-10) and/or methods (FIGS. 7-8)described herein to facilitate wireless communication there between.

At base station 1110, traffic data for a number of data streams isprovided from a data source 1112 to a transmit (TX) data processor 1114.According to an example, each data stream can be transmitted over arespective antenna. TX data processor 1114 formats, codes, andinterleaves the traffic data stream based on a particular coding schemeselected for that data stream to provide coded data.

The coded data for each data stream can be multiplexed with pilot datausing orthogonal frequency division multiplexing (OFDM) techniques.Additionally or alternatively, the pilot symbols can be frequencydivision multiplexed (FDM), time division multiplexed (TDM), or codedivision multiplexed (CDM). The pilot data is typically a known datapattern that is processed in a known manner and can be used at mobiledevice 1150 to estimate channel response. The multiplexed pilot andcoded data for each data stream can be modulated (e.g. symbol mapped)based on a particular modulation scheme (e.g., binary phase-shift keying(BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying(M-PSK), M-quadrature amplitude modulation (M-QAM), etc.) selected forthat data stream to provide modulation symbols. The data rate, coding,and modulation for each data stream can be determined by instructionsperformed or provided by processor 1130.

The modulation symbols for the data streams can be provided to a TX MIMOprocessor 1120, which can further process the modulation symbols (e.g.,for OFDM). TX MIMO processor 1120 then provides N_(T) modulation symbolstreams to N_(T) transmitters (TMTR) 1122 a through 1122 t. In variousembodiments, TX MIMO processor 1120 applies beamforming weights to thesymbols of the data streams and to the antenna from which the symbol isbeing transmitted.

Each transmitter 1122 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel.Further, N_(T) modulated signals from transmitters 1122 a through 1122 tare transmitted from N_(T) antennas 1124 a through 1124 t, respectively.

At mobile device 1150, the transmitted modulated signals are received byN_(R) antennas 1152 a through 1152 r and the received signal from eachantenna 1152 is provided to a respective receiver (RCVR) 1154 a through1154 r. Each receiver 1154 conditions (e.g., filters, amplifies, anddownconverts) a respective signal, digitizes the conditioned signal toprovide samples, and further processes the samples to provide acorresponding “received” symbol stream.

An RX data processor 1160 can receive and process the N_(R) receivedsymbol streams from N_(R) receivers 1154 based on a particular receiverprocessing technique to provide N_(T) “detected” symbol streams. RX dataprocessor 1160 can demodulate, deinterleave, and decode each detectedsymbol stream to recover the traffic data for the data stream. Theprocessing by RX data processor 1160 is complementary to that performedby TX MIMO processor 1120 and TX data processor 1114 at base station1110.

A processor 1170 can periodically determine which available technologyto utilize as discussed above. Further, processor 1170 can formulate areverse link message comprising a matrix index portion and a rank valueportion.

The reverse link message can comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message can be processed by a TX data processor 1138, whichalso receives traffic data for a number of data streams from a datasource 1136, modulated by a modulator 1180, conditioned by transmitters1154 a through 1154 r, and transmitted back to base station 1110.

At base station 1110, the modulated signals from mobile device 1150 arereceived by antennas 1124, conditioned by receivers 1122, demodulated bya demodulator 1140, and processed by a RX data processor 1142 to extractthe reverse link message transmitted by mobile device 1150. Further,processor 1130 can process the extracted message to determine whichpreceding matrix to use for determining the beamforming weights.

Processors 1130 and 1170 can direct (e.g., control, coordinate, manage,etc.) operation at base station 1110 and mobile device 1150,respectively. Respective processors 1130 and 1170 can be associated withmemory 1132 and 1172 that store program codes and data. Processors 1130and 1170 can also perform computations to derive frequency and impulseresponse estimates for the uplink and downlink, respectively.

It is to be understood that the embodiments described herein can beimplemented in hardware, software, firmware, middleware, microcode, orany combination thereof. For a hardware implementation, the processingunits can be implemented within one or more application specificintegrated circuits (ASICs), digital signal processors (DSPs), digitalsignal processing devices (DSPDs), programmable logic devices (PLDs),field programmable gate arrays (FPGAs), processors, controllers,micro-controllers, microprocessors, other electronic units designed toperform the functions described herein, or a combination thereof.

When the embodiments are implemented in software, firmware, middlewareor microcode, program code or code segments, they can be stored in amachine-readable medium, such as a storage component. A code segment canrepresent a procedure, a function, a subprogram, a program, a routine, asubroutine, a module, a software package, a class, or any combination ofinstructions, data structures, or program statements. A code segment canbe coupled to another code segment or a hardware circuit by passingand/or receiving information, data, arguments, parameters, or memorycontents. Information, arguments, parameters, data, etc. can be passed,forwarded, or transmitted using any suitable means including memorysharing, message passing, token passing, network transmission, etc.

For a software implementation, the techniques described herein can beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The software codes can be storedin memory units and executed by processors. The memory unit can beimplemented within the processor or external to the processor, in whichcase it can be communicatively coupled to the processor via variousmeans as is known in the art.

With reference to FIG. 12, illustrated is a system 1200 that canfacilitate searches for a cell in a wireless communication environment.For example, system 1200 can reside at least partially within a mobiledevice (e.g., 116). It is to be appreciated that system 1200 isrepresented as including functional blocks, which can be functionalblocks that represent functions implemented by a processor, software, orcombination thereof (e.g., firmware). System 1200 includes a logicalgrouping 1202 of electrical components that can act in conjunction. Forinstance, logical grouping 1202 can include an electrical component fordetecting PSCs 1204. In one aspect, the timing information associatedwith respective PSCs and/or other information respectively associatedwith PSCs can be detected by the electrical component for detecting PSCs1204. Further, logical grouping 1202 can comprise an electricalcomponent for detecting SSCs 1206. In accordance with one aspect,information associated with SSCs (e.g., phase information, correlationinformation, etc.) and/or information associated with CP length can bedetected by the electrical component for detecting SSCs 1206. Moreover,logical grouping 1202 can include an electrical component for selectinga cell based in part on the information respectively associated with theSSCs 1208. In one aspect, a cell (e.g., base station 102) can beselected based in part on the SSC information and/or other information,such as timing information respectively associated with PSCs, by theelectrical component 1208. Additionally, system 1200 can include amemory 1210 that retains instructions for executing functions associatedwith electrical components 1204, 1206, and 1208. While shown as beingexternal to memory 1210, it is to be understood that one or more ofelectrical components 1204, 1206, and 1208 can exist within memory 1210.

Turning to FIG. 13, illustrated is a system 1300 that can facilitatesearches for a cell in a wireless communication environment. System 1300can reside within a base station (e.g., 102), for instance. As depicted,system 1300 includes functional blocks that can represent functionsimplemented by a processor, software, or combination thereof (e.g.,firmware). System 1300 includes a logical grouping 1302 of electricalcomponents that can act in conjunction. Logical grouping 1302 caninclude an electrical component for generating PSCs 1304. Moreover,logical grouping 1302 can include an electrical component for generatingSSCs 1306. In one aspect, the generated SSCs can be unique to facilitatecell searches (e.g., a base station can be associated with one or moreSSCs that can be different from one or more SSCs associated with adisparate base station). Further, logical grouping 1302 can include anelectrical component for generating reference signals 1308. In oneaspect, the reference signals can be employed to facilitate detectingtiming information associated with PSCs and/or can facilitate cellsearches. Additionally, system 1300 can include a memory 1310 thatretains instructions for executing functions associated with electricalcomponents 1304, 1306, and 1308. While shown as being external to memory1310, it is to be understood that electrical components 1304, 1306, and1308 can exist within memory 1310.

FIG. 14 illustrates another example system that can facilitate searchingfor base stations in a wireless communication environment. The system1402 includes a component 1402 for detecting timing information relatedto primary synchronization channels (PSCs); a component 1404 foridentifying a cell based in part on phase information associated with aPSC; a component 1406 for employing a jointly time dithered primarysynchronization channel/secondary synchronization channel (PSC/SSC) thatconveys network context information; a component 1408 for ensuring thatthe PSC does not have a single frequency network (SFN) artifact in asynchronous system; a component 1410 for fixing the relative timedistance between the two consecutive PSCs regardless of cyclic prefix(CP) length; a component 1412 for determining correlation valuesrespectively associated with PSCs; a component 1414 for determiningcorrelation values respectively associated with SSCs; a component 1416for determining CP length a component 1418 for selecting the cell basedin part on the determined correlation values; and/or a component 1420for fixing relative time distance between two consecutive PSCs.

It is to be appreciated that the aforementioned components of system1400 can be hardware, software, or a combination thereof. It is furtherto be appreciated that the system 1400 does not require all respectivecomponents, and that many suitable combinations of subsets of thesecomponents can be employed in connection with carrying outfunctionalities described herein.

What has been described above includes examples of one or moreembodiments. It is, of course, not possible to describe everyconceivable combination of components or methodologies for purposes ofdescribing the aforementioned embodiments, but one of ordinary skill inthe art may recognize that many further combinations and permutations ofvarious embodiments are possible. Accordingly, the described embodimentsare intended to embrace all such alterations, modifications andvariations that fall within the spirit and scope of the appended claims.Furthermore, to the extent that the term “includes” is used in eitherthe detailed description or the claims, such term is intended to beinclusive in a manner similar to the term “comprising” as “comprising”is interpreted when employed as a transitional word in a claim.

What is claimed is:
 1. A method that facilitates a multi-stage cellsearch, comprising: detecting timing information related to primarysynchronization channels (PSCs); determining cyclic prefix (CP) lengthbased on a relative time distance between two consecutive PSCs; andidentifying a cell based in part on phase information associated with asecondary synchronization channel (SSC).
 2. The method of claim 1,comprising: employing a jointly time dithered primary synchronizationchannel/secondary synchronization channel (PSC/SSC) that conveys networkcontext information; and ensuring that the identified cell PSC does notcause interference with reception of a PSC for a second cell in asynchronous system.
 3. The method of claim 2 wherein an additional phaseshift of e^(jkθ) is applied to SSCs, where k=0, 1, 2 M−1, and 0=2π/M,wherein M relates to number of different phases that can be employed. 4.The method of claim 3, comprising applying a different phase shift toSSCs in each different base station in a network.
 5. The method of claim4, comprising applying a phase shift to an SSC, wherein a phase anglefor the phase shift is based in part on a PSC sequence.
 6. The method ofclaim 2, wherein a first SSC and a second SSC have differentcombinations of phase shift.
 7. The method of claim 2, wherein a firstSSC and a second SSC have same phase shift.
 8. The method of claim 7,comprising determining number of antennas associated with a base stationas a function of unique mapping between number of phases and number ofantennas used by the base station.
 9. The method of claim 8, wherein atleast three groups (α, β, γ) are represented by using a combination ofSSC order in a radio frame and phase modulation on top of SSCs.
 10. Themethod of claim 2, comprising using phase shift information associatedwith an SSC to facilitate determining location of an associated PSC in asymbol sequence.
 11. The method of claim 10, comprising perform timingdetection based in part on the detected PSC.
 12. The method of claim 1,wherein an SSC uses Chu sequences with different bases or differentcyclic shifts.
 13. The method of claim 1, comprising: determiningcorrelation values respectively associated with PSCs; determiningcorrelation values respectively associated with SSCs; and selecting thecell based in part on the determined correlation values.
 14. The methodof claim 1, comprising detecting and identifying which secondarysynchronization channel (SSC) sequence has been transmitted from aparticular cell to determine a hypotheses associated with the cell, andidentification of the cell.
 15. An electronic device configured toexecute the method of claim
 1. 16. The electronic device of claim 15,configured to execute the method of claim
 2. 17. A computer readablenon-transitory medium having stored thereon computer executableinstructions for carrying out the following acts: detecting timinginformation related to primary synchronization channels (PSCs);determining cyclic prefix (CP) length based on a relative time distancebetween two consecutive PSCs; and identifying a cell based in part onphase information associated with a secondary synchronization channel(SSC).
 18. The computer readable medium of claim 17, comprising computerexecutable instructions for carrying out the following acts: employing ajointly time dithered primary synchronization channel/secondarysynchronization channel (PSC/SSC) that conveys network contextinformation; and ensuring that the PSC does not cause interference withreception of a PSC for a second cell in a synchronous system.
 19. Thecomputer readable medium of claim 18, comprising computer executableinstructions for carrying out the following act: using phase shiftinformation associated with an SSC to facilitate determining location ofan associated PSC in a symbol sequence.
 20. The computer readable mediumof claim 17, comprising computer executable instructions for carryingout the following acts: determining correlation values respectivelyassociated with PSCs; determining correlation values respectivelyassociated with SSCs; and selecting the cell based in part on thedetermined correlation values.
 21. The computer readable medium of claim17, comprising computer executable instructions for carrying out thefollowing act: detecting and identifying which secondary synchronizationchannel (SSC) sequence has been transmitted from a particular cell todetermine a hypotheses associated with the cell, and identification ofthe cell.
 22. The computer readable medium of claim 17, comprisingcomputer executable instructions for carrying out the following act:perform timing detection based in part on the detected PSC.
 23. Anapparatus operable in wireless communication system, the apparatuscomprising: means for detecting timing information related to primarysynchronization channels (PSCs); means for determining cyclic prefix(CP) length based on a relative time distance between two consecutivePSCs; and means for identifying a cell based in part on phaseinformation associated with a secondary synchronization channel (SSC).24. The apparatus of claim 23, comprising: means for employing a jointlytime dithered primary synchronization channel/secondary synchronizationchannel (PSC/SSC) that conveys network context information; and meansfor ensuring that the identified cell PSC does not cause interferencewith reception of a PSC for a second cell in a synchronous system. 25.The apparatus of claim 23, comprising: means for determining correlationvalues respectively associated with PSCs; means for determiningcorrelation values respectively associated with SSCs; and means forselecting the cell based in part on the determined correlation values.26. The apparatus of claim 23, comprising means for detecting andidentifying which secondary synchronization channel (SSC) sequence hasbeen transmitted from a particular cell to determine a hypothesesassociated with the cell, and identification of the cell.
 27. Anapparatus operable in a wireless communication system, the apparatuscomprising: a processor, configured to: detect timing informationrelated to primary synchronization channels (PSCs); determine cyclicprefix (CP) length based on a relative time distance between twoconsecutive PSCs; and identify a cell based in part on phase informationassociated with a secondary synchronization channel (SSC); and a memorycoupled to the processor for storing data.
 28. The apparatus of claim27, the processor configured to: employ a jointly time dithered primarysynchronization channel/secondary synchronization channel (PSC/SSC) thatconveys network context information; and ensure that the identified cellPSC does not cause interference with reception of a PSC for a secondcell in a synchronous system.
 29. The apparatus of claim 27, theprocessor configured to: determine correlation values respectivelyassociated with PSCs; determine correlation values respectivelyassociated with SSCs; and select the cell based in part on thedetermined correlation values.
 30. The apparatus of claim 27, theprocessor configured to detect and identify which secondarysynchronization channel (SSC) sequence has been transmitted from aparticular cell to determine a hypotheses associated with the cell, andidentification of the cell.